[LLVMdev] Opinions Wanted: New asm Comments

[Chris Lattner]

On Jul 15, 2011, at 1:54 PM, David A. Greene wrote:

> Chris Lattner <clattner at apple.com> writes:
> 
>>> How would you prefer this work?  Even if the output were controlled by
>>> NDEBUG, I feel the added pattern comments make the asm file too
>>> cluttered even for day-to-day compiler developers.  This is really a
>>> feature to debug instruction selection problems.  That's why I put it
>>> under the control of a separate option.
>> 
>> It's not really clear how this should work.  I'm primarily concerned
>> that it will cause substantiate table/code bloat that doesn't make
>> sense for a shipping compiler.
> 
> Ok, in that case I think we'll need a TableGen flag to control whether
> this information gets generated.  A debug build would include it, a
> release build would not.

tblgen could unconditionally generate code that is protected by NDEBUG.

>> I agree that not all compiler hackers will want to see it, I'd
>> suggest adding a cl::opt that is only even available when built with
>> assertions on.
> 
> Assertions or Debug?  I would think we'd want it in the latter.

Assertions (which are on by default in a debug build) is the knob we have to play with.

-Chris